/*
 * Copyright 2002-2017 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.lang;

import javax.annotation.Nonnull;
import javax.annotation.meta.TypeQualifierDefault;
import java.lang.annotation.*;

/**
 * Spring通用注解，用于声明给定包下的参数和返回值默认应视为非空。
 *
 * <p>利用JSR-305元注解在Java中向支持JSR-305的通用工具指示空值约束，
 * 并被Kotlin用于推断Spring API的可空性。
 *
 * <p>应在包级别使用，并与参数和返回值级别的{@link Nullable}注解配合使用。
 *
 * @author Sebastien Deleuze
 * @author Juergen Hoeller
 * @since 5.0
 * @see NonNullFields
 * @see Nullable
 * @see NonNull
 */
@Target(ElementType.PACKAGE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Nonnull
@TypeQualifierDefault({ElementType.METHOD, ElementType.PARAMETER})
public @interface NonNullApi {
}
